Actualistic taphonomy of microvertebrates ingested by the barn owl (Tyto alba) in a forested area. Implications for the fossil record

Abstract

Rodents are common prey of nocturnal raptor birds, which ingest whole individuals and subsequentlyexpel partially digested remains as regurgitated pellets. This generates accumulations of skeletal elementsthat may become part of the fossil record. Inferring which predator was responsible of any givenfossil microvertebrate assemblage allows assessing potential biases and making paleoecological inferences.Neotaphonomic studies allow modelling the particularities characterizing different raptors underdifferent environmental conditions. Based on them, it is possible to suggest the predator involved in fossilmicrovertebrate assemblages by considering the taxonomic and anatomical abundance, the degree ofdigestive corrosion and that of breakage of skeletal remains. Yet, no detailed neotaphonomic studieson raptors had been made so far in NW Argentina, and other studies in South America have been mademainly in open and arid environments. This has forced paleontological studies to use analogues thatmight not be fully relevant. Here we present an actualistic study on rodent skeletal remains(NISP = 7540) recovered from modern pellets produced by the barn owl (Tyto alba), recovered at VillaPadre Monti (Tucumán, Argentina), a Yungas forest area partially affected by the presence of crops.The aim is to characterize the taphonomic traces of T. alba under these environmental conditions. Theassemblage is composed of at least five species of Cricetidae rodents and a varied representation of skeletalelements, especially of the post-cranium; it has a high relative anatomical abundance (58.7%). Skeletalbreakage levels are low, especially in the mandibles and post-cranium. Digestive corrosion is predominantlyabsent (62.1%) to light, although some elements with high degrees of digestive corrosion werefound, even in the extreme digestion category. These results generally compare well with other taphonomicstudies on the barn owl, and add data to the known variability of modern accumulations by thisStrigiformes. They are thus expected to have an impact on the interpretations of fossil faunas. 2024 Elsevier Masson SAS. All rights are reserved, including those for text and data mining, AI training,and similar technologies.